The only product of leucine metabolism is ketoisocaproate (KIC), and a minor product of KIC metabolism is .beta.-hydroxy-.beta.-methylbutyric acid (HMB).
HMB has been found to be useful within the context of a variety of applications. Specifically, as described in U.S. Pat. No. 5,360,613 (Nissen), HMB is useful for reducing blood levels of total cholesterol and low-density lipoprotein cholesterol. In U.S. Pat. No. 5,348,979 (Nissen et al.), HMB is described as being useful for promoting nitrogen retention in humans. U.S. Pat. No. 5,028,440 (Nissen) discusses the use of HMB to increase lean tissue development in meat-producing animals. Also, in U.S. Pat. No. 4,992,470 (Nissen), HMB is described as being effective in enhancing the immune response of mammals.
More recently, HMB has been used by athletes to increase strength. As described in Nissen et al., J. Appl. Physiol., 81(5): 2095-2104 (1996), the increase in the strength of the athlete is the result of an increase in muscle mass which occurs when weight, or resistance, training is combined with dietary supplementation of HMB. In other words, the stimulus to increase muscle mass brought about by weight, or resistance, training is magnified by HMB dietary supplementation.
However, within the context of some applications, it is desirable to increase the aerobic capacity of muscle without a concomitant increase in muscle mass. For example, where the aerobic capacity of cardiac muscle is compromised, it would be desirable to increase the aerobic capacity of the cardiac muscle without a concomitant increase in its muscle mass.
In view of the foregoing, there exists a need for a method by which the aerobic capacity of muscle can be increased without a concomitant increase in muscle mass. The present invention provides such a method as well as a related method thereof. These and other advantages of the present invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.